Fusion process



H. H. DOW.

FUSION PROCESS.

APPLICATION FILED AUG-SHIEHB.

1,87%619, Patented; May SL, 1921.

IN VENTQZ/ UNHE stares PATENT @FFECCE.

HERBERT H. DOW, OF MIDLAND, MICHIGAN, ASSIGNOR TO THE DOW CHEMICAL COMPANY, OF MIDLAN D, MICHIGAN, A CORPORATION OF MICHIGAN.

FUSION PROCESS.

Specification of Letters Patent.

Patented May 31, 19211.

Application filed August 31, 1918. Serial No. 252,225.

To all whom it may concern:

Be it known that I, HERBERT H. citizen of the United States, and a resident of Midland, county of Midland, and State of Michigan, have invented a new and useful Improvement in Fusion Processes, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

There are many fusion processes in which the mixture of materials, upon being heated together in order to cause their interfusion, develop a tendency to oxidize excessively when exposed to the oxygen in the atmosphere. This is particularly true of fusion processes having to do with the preparation .of organic compounds, such as fusions in caustic soda, or other alkali metal hydrate. It has accordingly been found advisable to blanket the fusion mixture with a suitable gas or vapor in order to protect such mass from oxidation, and I- have found that for this purpose a sufficiently heavy hydrocarbon vapor, for instance gasolene vapor, is very satisfactory. However, the fusion kettles require of course to be vented, and, as might be expected, it has been found that the hydrocarbon vapor, upon being mixed with air, is very apt to form an explosive mixture. The present invention accordingly has as its object the provision of means for circum- Venting this difiiculty and preventing not only oxidation of the fused mass, but also the explosions that occur where a hydrocarbon Vapor is used to blanket such mass.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the steps hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail one approved mode of carrying out the invention, such disclosed mode, however, constituting but one of the various ways in which the Dow, a

cheap enough as ordinarily made, to be available for commercial use. I have found, however, that while ordinary stack gases contain a small percentage of oxygen sufiicient to cause some oxidation, if admitted directly over the fused mass, such oxygen content is so small that the formation of an explosive mixture between the same and a hydrocarbon vapor, such as hereinbefore referred to, is practically impossible.

In the drawing, a fusion pot l of typical form is shown seated in a suitable furnace chamber 2, whereby heat may be applied to the bottom and sides thereof so that the contents 3 of the pot may be brought to the desired temperature. The contents of the pot are sealed against contact with the outer atmosphere by a close fitting cover 4, from the center of which leads a. duct 5 connected at its outer end with a larger duct, or rather flue, 6, through which stack gases from any available source are conducted. These stack gases, before reaching the point of connection of said duct therewith, will ordinarily be desirably brought in contact with a suitable reagent capable of absorbing carbon dioxid, such for example as magnesium hydrate, so as to eliminate from such stack gases the carbon dioxid present. In this way a valuble by-product in the form of magnesium carbonate is produced, and the residue is practically pure nitrogen, with only a small admixture of oxygen.

If desired, this residual gas may be utilized to directly blanket the fusion mixture in the pot, but in most cases a neutral hydrocarbon vapor, such as gasolene vapor, is preferably introduced into the pot to immediately cover the fusion mixture. Such introduction is conveniently effected by simply dripping in a quantity of liquid gasolene, which of course immediately vaporizes. In any event, it is necessary to provide a vent for the excess vapor that may be formed, and the duct 5 accordingly serves this purpose, any excess of vapor being expelled into the larger fiue 6 through which the stack gases pass; or, in the event of a reflux of the vapor into the pot, the stack gases will not form an explosive mixture with the hydrocarbon. However, the amount of oxygen in the mixture will be reduced to quite an in consequential percentage, so no harm results from contact between the same and the mixture.

gards the method herein disclosed, provided the step or steps stated by any of the following claims or the equivalent of such stated step V or steps be employed.

I therefore particularly point out and distinctly claimas my invention 1. In a process involving the fusion together of a mixture of materials of the character described, so as to produce a chemical reaction between said materials the step which consists in blanketing the fusion mixture with flue gases, substantially as described.

2. In a process involving the fusion together of a mixture of materials of the character described, the step which consists in blanketing the fusion mixture with flue gases, from which the carbon dioxid has been removed, substantially as described.

3. In aprocess involving the fusion together of a mixture of the character described, the steps which consist in directly covering the fusion mixture with a layer of hydrocarbon vapor and venting the latter into an atmosphere too low in oxygento form an explosive mixture therewith.

4. In a process involving the fusion together of a mixture of the character described, the steps which consist in directly covering the fusion mixture with a layer of hydrocarbon vapor, and ventin the latter into an atmosphere composed of ue gases.

gether of a mixture of materials of the character described, the step which consists in blanketing the fusion mixture with hydrocarbon vapor. 7. In a process involvmg the fusion together of a mixture of materials of the character described, the step which consists in blanketing the fusion mixture with heavy hydrocarbon vapor.

8. The method of-preventing oxidation of an alkaline fusion mixture. which consists in blanketing thesame with hydrocarbon va 0 por, and covering the latter with flue gases.

11. The method of preventing oxidation of an alkaline fusion mixture which consists in blanketing the same with hydrocarbon vapor, and covering the latter with flue gases from which the carbon dioxid has been removed.

Signed by me, this 24th day of August,

HERBERT H. DOW.

p r. p 9. The method of preventing oxidatlon of 

